Preparation

1. Warm the beer in a Hexclad 1 Litre Hybrid Saucepan over a medium heat, then pour into a mug or jug whilst you turn the heat down to low and melt the butter in the same pan. 
2. When the butter becomes liquid, add in the flour and whisk together, before adding the warmed beer back in, a few splashes at a time - mixing each time to make sure there are no lumps. 
3. Once combined, stir in the mustard, chives or cornichons, and worcestershire sauce then remove from the heat. 
4. Heat the grill to its hottest setting, then place the un-topped slices of bread onto a baking sheet and grill for a few minutes until they turn golden brown. Remove from the oven, turn the bread over and top with the cheese mixture. 
5. Place back under the grill and cook for another minute or two until the cheese turns golden and bubbly. 
6. Serve with a salad, if desired.

For a pilsner, gruyere and cornichon rarebit variation:

Swap the porter stout with pilsner, the wholegrain mustard with Dijon, the chives for chopped cornichons and the cheddar for gruyere. Use white sourdough instead of seeded.